CN108010307B

CN108010307B - Fleet control

Info

Publication number: CN108010307B
Application number: CN201710958342.8A
Authority: CN
Inventors: 阿波娃·萨克塞纳; 李虹; 帝普·戈斯瓦米
Original assignee: NXP BV
Current assignee: NXP BV
Priority date: 2016-10-31
Filing date: 2017-10-13
Publication date: 2022-02-01
Anticipated expiration: 2037-10-13
Also published as: EP3316062A1; EP3316062B1; CN108010307A; US20180120861A1; US10459454B2

Abstract

A method and apparatus for controlling vehicles traveling in a fleet of vehicles is provided. A first set of information is received at a first vehicle in a fleet of vehicles, the first set of information being related to at least one other vehicle in the fleet of vehicles. Selecting one of a plurality of control algorithms depending on the first set of information, wherein each of the plurality of control algorithms corresponds to a respective fleet communication topology. Controlling the first vehicle in response to the selected one of the first set of information and the control algorithm.

Description

Fleet control

Technical Field

The present application relates to automatic control of vehicles in a fleet of vehicles, and in particular to the use of inter-vehicle communication in automatic formation of vehicles.

Background

Intelligent Transportation Systems (ITS) are systems intended to improve road safety zones by broadcasting real-time information about road conditions. For example, in such systems, a car or similar vehicle may broadcast information such as location, speed, road conditions, events and/or accidents, and the like. This information can be shared between vehicles using so-called inter-vehicle (V2V) communication and between vehicles and other units using vehicle-to-infrastructure (V2I) communication, such as roadside entities or traffic control units. These communication systems may use IEEE 802.11p Dedicated Short Range Communication (DSRC) technology.

One application of the ITS may provide vehicle fleet. Such a fleet of vehicles may automatically group several vehicles to travel in an actively coordinated manner, such as forming a train of vehicles. Vehicle fleet may be required in order to improve road use capacity and ease traffic, improve fuel efficiency, safety, and driver comfort.

To coordinate such vehicle formation, a vehicle formation control algorithm may be provided in each vehicle in the fleet to control the vehicle to remain in the fleet. These control algorithms may control vehicle parameters such as speed and acceleration. Such control algorithms may control the vehicle in response to receiving information about the fleet behavior from sensors on the vehicle or from other members of the fleet and/or other entities. For example, the algorithm may operate based on information received from radar sensors of the vehicle and/or V2V communications.

The goal of such control algorithms may be to keep the vehicles in the fleet so that the distance between the member vehicles of the fleet is relatively small. A smaller distance or gap between the vehicles may result in less airflow resistance and less fuel consumption.

Adaptive Cruise Control (ACC) systems in a vehicle may use radar and/or laser sensors to follow the vehicle directly in front of it. The ACC may not see any of the vehicles in the platoon that precede the vehicle immediately in front of it, which may result in a one-by-one propagation of any action by the vehicles guiding the platoon. Such one-by-one propagation may be accommodated by providing a large gap or travel distance between fleet members.

In ITS, a Common Awareness Message (CAM) may be broadcast at a rate of 10Hz, through which each vehicle may broadcast information about itself using a control channel. Such information may include the position, speed, acceleration, and motion of the vehicle. Using the CAM, a vehicle may use one message to broadcast such information to multiple vehicles simultaneously.

In Cooperative Adaptive Cruise Control (CACC), a vehicle may use information not only from its front vehicles, but also from other members of the fleet. Although CACC systems may limit the propagation of interference throughout the vehicle chain due to additional information compared to ACC in some cases, the addition of messages used to convey such information may suffer from network delays or problems associated with incomplete messaging media.

Embodiments of the present application aim to provide a vehicle fleet control method while taking into account these real world constraints.

Disclosure of Invention

According to a first aspect of the present application, there is provided a method for controlling vehicles traveling in a fleet of vehicles, comprising:

receiving a first set of information at a first vehicle in a fleet of vehicles, the first set of information relating to at least one other vehicle in the fleet of vehicles; selecting one of a plurality of control algorithms depending on the first set of information, wherein each of the plurality of control algorithms corresponds to a respective fleet communication topology; and controlling the first vehicle in response to the selected one of the first set of information and the control algorithm.

The first set of information may include at least one of radar information and one or more inter-vehicle messages. The radar information may be provided, for example, from a radar unit of the first vehicle. The inter-vehicle message may be received from one or more other vehicles in the fleet via a communication channel. The method may include storing a first set of information in a memory.

The method may additionally comprise: receiving a second set of information at the first vehicle; selecting another control algorithm of the plurality of control algorithms in dependence on the second set of information; and controlling the first vehicle in response to the second set of information and another selected one of the control algorithms. In some examples, the set of information may be received at the first vehicle periodically and/or cyclically. In some embodiments, the selection of the control algorithm may be made in response to receiving the set of information. In other embodiments, the selection of the control algorithm may be made whenever the type and/or number of messages in the information set changes.

The method may additionally comprise: determining that no inter-vehicle messages have been received as part of the second set of information; and selecting a predictive control algorithm from a plurality of control algorithms, the predictive control algorithm configured to predict other information of the second set of information based on the stored first set of information. In some examples, the inter-vehicle message may have been lost in transmission via the communication channel and may not reach the receiver. In some cases, radar information from a radar sensor may be obtained. The controller may select the predictive control algorithm in response to not receiving any inter-vehicle messages. The inter-vehicle message may include information about the driving status of the vehicle sending the message. If no inter-vehicle messages are received, the prediction algorithm may predict the driving state of one or more vehicles in the fleet depending on one or more previously stored sets of information. The predicted other information may correspond to information carried in the inter-vehicle message.

The memory may be additionally configured to store control boundary information. The step of controlling the first vehicle may additionally comprise controlling the first vehicle additionally in response to the control boundary information. At least some of the control boundary information may be received from at least one other vehicle in the fleet. For example, each vehicle in the fleet may be configured to send their boundary conditions to each other vehicle. In other examples, the boundary information may be sent from a central entity.

The method may additionally comprise: determining that no inter-vehicle messages have been received as part of the second set of information; and requesting information from at least one other vehicle in the fleet. In some cases, the fleet control system may request the driving status from one or more surrounding vehicles when it is determined that inter-vehicle messages or information related to the driving status of other vehicles are not available.

The method may additionally comprise: information associated with the first vehicle is transmitted to at least one other vehicle in the fleet of vehicles. The first vehicle may transmit an inter-vehicle message including, for example, driving status and/or boundary information of the first vehicle. The information associated with the first vehicle may include at least one of inter-vehicle messages and control boundary information. The inter-vehicle message includes information related to a driving state of the first vehicle. In some examples, the inter-vehicle message may be a public awareness message (CAM).

According to a second aspect, there is provided an apparatus for controlling the behaviour of a first vehicle in a platoon, the apparatus comprising: at least one receiver configured to receive a first set of information relating to at least one other vehicle in a fleet of vehicles; and a controller configured to: selecting one of a plurality of control algorithms depending on the first set of information, wherein each of the plurality of control algorithms corresponds to a respective fleet communication topology; and providing a control signal configured to control the first vehicle in response to the first set of information and the selected control algorithm.

The first set of information may include at least one of radar information and one or more inter-vehicle messages. The apparatus may additionally comprise: a memory configured to store a first set of information. When the receiver receives the second set of information, the controller may be further configured to: selecting another control algorithm of the plurality of control algorithms in dependence on the second set of information; and providing a control signal configured to control the first vehicle in response to another selected one of the second set of information and the control algorithm.

The controller may be further configured to determine that no inter-vehicle message has been received as part of the second set of information and to select a predictive control algorithm from a plurality of control algorithms, the predictive control algorithm configured to predict other information of the second set of information based on the stored first set of information. The predicted other information may correspond to information carried in the inter-vehicle message.

The memory may be additionally configured to store control boundary information. The controller may be further configured to control the first vehicle further in response to the control boundary information. The receiver may be further configured to receive at least some of the control boundary information from at least one other vehicle in the fleet of vehicles. The controller may be further configured to determine that no inter-vehicle message has been received as part of the second set of information, and to request information from at least one other vehicle in the fleet of vehicles.

The apparatus may additionally comprise: a transmitter configured to transmit information associated with the first vehicle to at least one other vehicle in the fleet of vehicles. The information associated with the first vehicle may include at least one of inter-vehicle messages and control boundary information. The inter-vehicle message may include information related to a driving status of the first vehicle. The apparatus may additionally comprise: a vehicle controller configured to receive a control signal and to control a behavior of the first vehicle in response to the control signal.

Drawings

Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is an example of a communication topology that may be implemented in a fleet of vehicles;

FIG. 2 is a flow diagram depicting method steps according to an embodiment;

FIG. 3 illustrates an example of a communication message that may be sent between vehicles in a fleet of vehicles; and

fig. 4 shows an example of a vehicle controller according to the embodiment.

It should be appreciated that similar features are indicated for features spanning more than one figure, such as reference numerals.

Detailed Description

Various communication network topologies may be implemented in vehicle fleet.

Fig. 1a, b and c show a first vehicle 101, a second vehicle 102, a third vehicle 103, a fourth vehicle 104 and a fifth vehicle 105 traveling in numerical order. The first vehicle 101 is considered to be a fleet of vehicles.

FIG. 1a shows an example of a front vehicle-following vehicle fleet communication topology. In this topology, communication 110 occurs between the first vehicle 101 and the second vehicle 102, communication 111 occurs between the second vehicle 102 and the third vehicle 103, communication 112 occurs between the third vehicle 103 and the fourth vehicle 104, and communication 113 occurs between the fourth vehicle 104 and the fifth vehicle 105.

In this example, the communication takes the form of radar detection by the trailing vehicle indicating that the radar of the vehicle has detected the leading vehicle. However, it will be appreciated that this is by way of example only, and that the communication may take any form, for example, it may be a V2V message or other form of congestion detection. In this example, each vehicle in the fleet, except for the fleet lead, receives information about the vehicle immediately in front of it. An example of this topology may be used for Adaptive Cruise Control (ACC).

FIG. 1b shows an example of a lead-following vehicle fleet communication topology. In this topology, each of the

fleet vehicles

102, 103, 104, and 105, other than the lead vehicle 101, receives a

respective message

120, 121, 122, and 123 from the fleet lead vehicle 101. Further, each of the vehicles 101 to 105 may perform radar detection on the preceding vehicle.

FIG. 1c shows an example of a front-front vehicle-following vehicle fleet vehicle communication topology. In the topology of fig. 1c, the fleet leader 101 provides a message 130 to the vehicle 102 immediately behind it and a message 131 to the vehicle 103 that is behind it and one vehicle away from it. The second vehicle 102 in the fleet provides the message 132 to the fourth vehicle 104, which fourth vehicle 104 is a vehicle that is one vehicle behind and spaced apart from the second vehicle 102. The third vehicle 103 in the platoon provides a message 133 to a fifth vehicle 105, which fifth vehicle 105 is a vehicle behind the third vehicle 103 and one vehicle away from it. Further, each of the vehicles 101 to 105 may perform radar detection on the preceding vehicle.

In either communication topology, each message may include information related to the sending vehicle, such as the location and/or speed of the vehicle and/or the motion of the vehicle, or other information about the fleet. Although fig. 1a, b and c show three examples of such communication network topologies, it should be understood that other network topologies may exist and are compatible with embodiments of the present application.

The behavior of the fleet may depend on the implemented fleet communication topology. For example, in a fleet communication topology where more information is available, the fleet may have more precise control. However, in some systems, fleet behavior may depend on accurate communications and the following assumptions: messages between the vehicles of the fleet will be received in an accurate and timely manner. This may not always be the case.

Wireless communication deficiencies may affect fleet implementation, and fleet control may be sensitive to network deficiencies (e.g., congestion). The V2V message delivery rate may vary with the distance between the sender and the receiver. In some examples, the order of the broadcast messages may change due to MAC layer backoff in busy channels.

Furthermore, when ITS is employed, then ITS networks may begin to suffer from network congestion. For example, in a situation including a 1km highway with 2x3 lanes and an average car distance of 25 meters, approximately 240 cars may be in the access range of every other vehicle and the CAM message may be sent at a packet rate of 10 Hz. The default modulation rate for communication on the control channel may be 6 Mbps. Simulation results may show that in such a crowded situation, 50% of the messages may be lost (due to message collisions in the air). This may be due to channel capacity limitations and CSMA-CA multiple access protocol overhead.

A de-centralized congestion control (DCC) solution may be implemented to adjust message rate, transmit power, or modulation data rate according to measured channel busyness ratio, however, reducing message rate may increase information update time between fleet members, which may result in less secure fleet situations. Reducing transmit power may additionally reduce communication range.

Embodiments of the present application may be directed to addressing situations where there is incomplete communication in which, for example, messages may be lost or delayed. In such embodiments, it has been recognized that vehicle fleet control algorithms defined using a particular network or communication topology may not be optimal for each communication scenario and may provide a flexible approach to fleet control that may be adapted to actual communication scenarios.

Embodiments of the present application may control fleet behavior of vehicles using control algorithms associated with communication topologies corresponding to sets of information received at the vehicles. For example, the vehicle may receive a first set of information from the fleet lead including radar information and a V2V message, and may select a control algorithm corresponding to a lead-to-follow vehicle topology associated with the first set of information. The lead-following vehicle topology may be associated with the first set of information because the first set of information includes the type of information required for the lead-following vehicle topology, e.g., radar information and V2V thinking from fleet leads.

The vehicle may then receive a second set of information that includes only radar information. For example, a V2V message from a fleet leader may have been lost due to an undesirable communication condition. The fleet control system may select a control algorithm corresponding to a front vehicle-following vehicle topology associated with the second set of information. The front vehicle-following vehicle topology may be associated with a second set of information, as the second set of information includes the type of information required for the front vehicle-following vehicle topology, e.g., radar-only information.

In embodiments, a control algorithm for controlling the in-line behavior of the vehicles may be selected depending on the set of information received at the vehicle, and such determination may be made periodically, or may be made in response to receiving the set of information.

FIG. 2 is a flow chart depicting method steps that may be performed by a fleet control system. The fleet control system may form part of a vehicle traveling in a fleet and may be configured to control the vehicles in the fleet.

At step 201, a fleet control system may receive fleet information. In some examples, fleet information may be received as one or more of radar information from a radar system of a vehicle, inter-vehicle messages from one or more other vehicles in a fleet, and/or sensor data from a vehicle. In some examples, the information may be received and collected at an information collector. The information collector may act as an interface between a fleet controller of a fleet control system and a receiving system of a vehicle (e.g., a V2V receiver and/or a radar receiver).

The fleet control system may operate according to a plurality of fleet control topologies (e.g., those described with respect to fig. 1). To do so, the fleet control system may include a plurality of control algorithms, where each algorithm is associated with a fleet control topology.

At step 202, the fleet control system may identify a control algorithm to use based on the received message. The control system may use the received messages to identify a fleet communication topology, and may select a control algorithm associated with the fleet communication topology. In an embodiment, the control algorithm associated with the fleet communication topology that most closely matches the type and number of messages received may be selected.

Referring to fig. 1, it can be seen that a fleet communication topology may be associated with a received message type. For example, in the front vehicle-following vehicle topology of fig. 1a, only radar information from the front vehicle in the platoon is received. In the lead-following vehicle topology, radar from the leading vehicle and V2V messages from the fleet lead vehicle are received. Although multiple messages may be sent to vehicles in a fleet, it should be understood that not all messages sent to the vehicles will reach the vehicles.

If the fleet control system of vehicles is operating with a control algorithm associated with a lead-follow vehicle topology, but the V2V message from the fleet lead is lost, the operation of the lead-follow vehicle control algorithm will be suboptimal. In an embodiment, the fleet control system may identify a received message and select a control algorithm corresponding to a communication topology associated with the received message.

At step 203, the fleet control system may control fleet behavior of the vehicles depending on the received message and the selected control algorithm. The control may for example comprise controlling the speed and acceleration of the vehicle.

Fig. 3 illustrates an example of a message or set of information that may be received at each vehicle in a fleet of vehicles.

Fig. 3 shows that three sets of

messages

301, 302 and 303 are received at four

vehicles

101, 102, 103 and 104 in a fleet. The first vehicle 101 may be a lead vehicle, behind which the second vehicle 102, the third vehicle 103 and the fourth vehicle 104 follow in succession.

For each information set 301, 302, and 303, the fleet lead 101 may send a

first V2V message

310, 320, 330 to the

other vehicles

102, 103, and 104 in the fleet. The second vehicle 102 may send a

second message

313, 323, 333 to

subsequent vehicles

103 and 104 in the platoon. The third vehicle 103 may send a

third message

315, 325, 335 to a subsequent vehicle 104 in the fleet.

For the first set of messages 301, the fourth vehicle 104 may receive a first message 310, a second message 313, and a third message 315. In this case, the fleet control system of the fourth vehicle may select a control algorithm corresponding to the communication topology in which messages from one or more of the preceding vehicles are used.

For the second set of messages 302, the fourth vehicle 104 may receive the first message 320, the second message 323 out of order, and may not receive the missing third message 315. In this case, the fleet control system of the fourth vehicle may select a control algorithm corresponding to a communication topology in which messages from the fleet leading vehicle are used instead of the other leading vehicles.

For the third set of messages 303, the fourth vehicle 104 may not receive the missing first message 330, second message 333, or third message 330. In this case, the fleet control system of the fourth vehicle may select a control algorithm corresponding to a communication topology in which no messages have been received. In this case, the fleet controller system may use a special algorithm that includes predictive information of the preceding vehicle. This predictive information may be generated from stored messages and information, for example, assuming that the leading vehicle remains moving at the same acceleration as indicated in the previous message. In this case, the fleet control system may request information related to the lead vehicle from neighboring vehicles that have good communication with the lead vehicle.

FIG. 4 depicts an example device that may be used to implement a fleet control system. Fig. 4 includes a message transceiver 401, such as the V2V message transceiver. In some embodiments, the message transceiver may include an antenna and a receive processing path. In some cases, the message transceiver may share circuitry with the transmitter of the V2V message. The message transceiver 401 may be coupled to provide received messages and/or information to the information collector 402 along with the sensor 403. The sensors may include sensors, such as radar sensors, and may additionally include a receive path to process information received from the sensors and provide this information to the information collector 402. The information collector may be configured to collect information received from the sensors 403 and/or the message transceiver 401 and provide this information to the fleet controller 404. In some embodiments, the fleet controller 404 may be coupled to provide control information to the message transceiver 401 and the sensors 403.

The information collector 402 may be coupled to a memory 405. The memory may be configured to store received information including, for example, V2V messages and sensor data. The memory 405 may additionally be configured to store a plurality of control algorithms, each control algorithm corresponding to a respective communication topology. An algorithm switch 406 may be coupled between the fleet controller 404 and a memory 405. The algorithm switch may be configured to store a selected control algorithm for the fleet controller. In some embodiments, the algorithmic switch may be a memory having a faster access speed than memory 405.

The fleet controller 404 may be coupled to a low-level vehicle controller 407. The low-level controllers may be configured to control the operation of the vehicles in response to control information from the fleet controller 404.

In operation, the fleet controller 404 can switch between control algorithms optimized for respective received information and/or messages. The control algorithms may each correspond to a communication topology, e.g., the control algorithms may each optimize to operate on received information or messages associated with the respective communication topology. The control algorithm may be used by a fleet controller to determine control parameters of the vehicle to maintain it in a fleet. For example, the selected control algorithm may be used to calculate acceleration and other control parameters that may be used to cyclically control the low-level vehicle controller. The low-level vehicle controller may control the mobility of the vehicle. The received messages and/or information (e.g., position, velocity, acceleration, and/or time stamp) may be stored in memory.

A fleet control system of vehicles may receive a set of messages from surrounding vehicles or from sensor systems within the vehicles. Based on this set of messages, the control system may determine the most appropriate control method or algorithm. In some examples, the control algorithm may be embodied by a control matrix that provides a mechanism to control the vehicle based on information received in the first set of messages. Each control algorithm may be associated with a certain communication topology. Thus, if a set of messages similar to the first communication topology is received, the fleet control system may select a control algorithm corresponding to the first communication topology. In this way, if a message is dropped or lost, the fleet control system may select the control algorithm that will provide the most accurate control based on the received message.

The selection of the control algorithm may be made in response to each set of messages received, as each set may miss a different message. Matching the received message type to the communication topology and corresponding control algorithm may allow for accurate use of information (via messages) available at the vehicle. The messages in the first set of messages may additionally be filtered such that messages of sufficient quality are used to select the control algorithm. The selected algorithm and the received set of messages may be used to control the vehicle, for example, to calculate acceleration. In the case where no messages are received (e.g., all messages are lost), the fleet control system may predict the behavior of one or more other vehicles in the fleet based on a previously received set of messages stored in memory. A set of messages may be received periodically. If no messages are received within a number of cycles, the fleet control system may control the vehicles in a safety conscious manner, for example, increasing the allowed following distance.

In the above, it has been described that the fleet controller may control the operation of the vehicle depending on the received information and the selected control algorithm. In another example, the control may additionally depend on control boundary information. The control boundary information may be stored in memory 405. The control boundary information may represent an operational boundary of the vehicle, such as a maximum acceleration, a mass and/or a size of the vehicle. In some examples, fleet control boundary information may be received from other vehicles in the fleet or may be received from a central control or information source. In some cases, the vehicle may know its own control boundary information. The control boundary information may include, for example, the maximum acceleration and negative acceleration of one or more fleet members for different road conditions (e.g., different bank angles or weather conditions). The control boundaries may be used to adjust control metrics to improve security.

In the foregoing, control algorithms have been discussed, wherein each control algorithm is optimized for a respective communication topology. In some examples, each predefined algorithm may be optimized to be communication topology-oriented. In some embodiments, each control algorithm may be implemented by using a corresponding control matrix. The control matrix may satisfy known string stability conditions using a general quadratic lyapunov equation to achieve string stability for fleet control. Additionally, the control matrix may be a closed loop system matrix. The closed loop system matrix may operate using boundary condition information (e.g., boundary conditions for a closed loop system).

Claims

1. A method for controlling vehicles traveling in a fleet of vehicles, comprising:

receiving a first set of information at a first vehicle in a fleet of vehicles, the first set of information being related to at least one other vehicle in the fleet of vehicles;

selecting one of a plurality of control algorithms depending on a type of information in the first set of information, wherein each of the plurality of control algorithms corresponds to a respective fleet communication topology, wherein the type of information in the first set of information is required by the fleet communication topology and corresponds to the selected control algorithm; and

controlling the first vehicle in response to the first set of information and the selected one of the plurality of control algorithms.

2. The method of claim 1, wherein the first set of information comprises at least one of radar information and one or more inter-vehicle messages.

3. The method of any preceding claim, further comprising:

storing the first set of information in a memory.

4. The method of claim 3, further comprising:

receiving a second set of information at the first vehicle;

selecting another control algorithm of the plurality of control algorithms in dependence on the second set of information; and

controlling the first vehicle in response to the second set of information and the selection of another one of the plurality of control algorithms.

5. The method of claim 4, further comprising:

determining that no inter-vehicle messages have been received as part of the second set of information; and

selecting a predictive control algorithm from the plurality of control algorithms, the predictive control algorithm configured to predict other information of the second set of information based on the stored first set of information.

6. The method of claim 5, wherein the other information predicted corresponds to information carried in an inter-vehicle message.

7. The method of claim 6, wherein the memory is further configured to store control boundary information.

8. The method of claim 7, wherein the step of controlling the first vehicle further comprises controlling the first vehicle further in response to the control boundary information.

9. The method of claim 4, further comprising:

information from at least one other vehicle in the fleet is requested.

10. An apparatus for controlling behavior of a first vehicle in a fleet of vehicles, the apparatus comprising:

at least one receiver configured to receive a first set of information related to at least one other vehicle in the fleet of vehicles; and

a controller configured to:

providing a control signal configured to control the first vehicle in response to the first set of information and the selection of one of a plurality of control algorithms.